1. Technical Field
The present invention relates to a vibrator element, and a vibrator, an oscillator, and an electronic apparatus each equipped with the vibrator element.
2. Related Art
In the past, as a vibrator element there has been known a piezoelectric vibrator element (hereinafter referred to as a vibrator element) including a base section, an arm section extending from the base section, and an excitation section supported by a first section of the arm section in a length direction thereof wherein the excitation section has a pair of electrode films sandwiching a piezoelectric film (see, e.g., JP-A-2009-239860 (Document 1)).
The vibrator element of Document 1 has a configuration in which the piezoelectric film of the excitation section (hereinafter referred to as excitation electrodes) extends and contracts to thereby cause a flexural vibration of the arm section (hereinafter referred to as vibration arms) in a thickness direction thereof.
The Q-value (a dimensionless number representing the state of the vibration; the larger the value is, the more stable vibration the value represents) of such a vibrator element as described above is lowered compared to the state in which the vibration arm is stand-alone by providing the excitation electrodes.
As the excitation electrodes of such a vibrator element as described above, there are frequently used films (films each having a foundation layer made of Ti and an upper layer made of Au stacked on each other) made of Ti (titanium)/Au (gold) as the pair of electrode films sandwiching the piezoelectric film.
However, according to an observational study by the inventors, the configuration using Ti/Au as the pair of electrode films of the excitation electrodes has a problem that the degree of deterioration of the Q-value is large.